Truing device for peripheral type grinding wheels



y 1953 D. A. TRESCOTT 2,841,923

TRUING DEVICE FOR PERIPHERAL TYPE GRINDING WHEELS Filed Dec. 26, 1956Dana la it Trescozt J S/r12 7 TRUING DEVICE FUR PERIPHERAL TYPE GRINDINGWHEELS Donald A. Trescott, Chicago, Ill., assignor to Super-Cut, Inc.,Chicago, IiL, a corporation of Illinois Application December 26, 1956,Serial No. 630,555 10 Claims. (Cl. 51-168) The improved truing devicecomprising the present invention has been designed for use primarily inconnection with the truing of peripheral type diamond grinding wheels.The invention is, however, capable of other uses and the same may, ifdesired, with or without suitable modification, be employed for truingand/or balancing shaftmounted abrasive or other rotary tools whichdiffer widely in their construction and design, as well as in the use towhich they may be put. Irrespective, however, of the specificapplication of the present truing device, the essential features thereofare at all times preserved.

In the operation of peripheral type diamond grinding wheels, onlyextremely small eccentric tolerances are permitted between the axis ofthe effective wheel periphery and the axis of the central drive shaft orspindle, both from the standpoint of accurate control of the desiredwork contour and of vibrational effects in the grindwheel itself duringfree rotation thereof. Thus, where there is any discrepancy or lack ofcoincidence between the axis of the peripheral ring-like diamond matrixof the wheel and the axis of the central mounting opening in the wheel,the grinding wheel cannot be mounted for proper operation on the centraldrive spindle or on the adaptor associated with such spindle and, atleast for certain types of precision work, the wheel must be discarded.Similarly, where there is a comparatively wide tolerance between thediameter of the spindle, or the cylindrical mounting surface of thegrinding wheel adaptor and the diameter of the central opening in thegrinding wheel, it is difi'icult'to mount the wheel on the spindle in acondition of either trueness or balance, or both, and much time isconsumed in an effort to obtain such trueness and balance.

The present invention is designed to overcome the above-notedlimitations that are attendant upon the use of conventional peripheraldiamond grinding wheels and, toward this end it contemplates theprovision of a novel mounting for the grinding wheel whereby the lattermay be operatively mounted on the drive spindle and adjusted thereonthrough very fine limits of adjustment and thereby brought to a preciseposition of trueness and condition of balance.

The provision of a grinding wheel mounting of the character brieflyoutlined above being among the principal objects of the invention, it isanother object to provide an adjusting means for the grinding wheel onits drive spindle or adaptor whereby comparatively large increments ofmovement of the adjusting tool employed for adjusting purposes willresult in comparatively small increments of radial shifting movement ofthe wheel relative to the central axis of the mounting spindle in thedesired direction.

Yet another object of the invention, in a truing device of thischaracter, is to provide an adjusting means for varying the radialposition of the grinding Wheel so that its eccentricity may be broughtwithin tolerable limits and tates Patent e ce whereby the necessaryadjustments may be made at the time of initial installation of the wheelon the spindle or at any time thereafter, without requiring completedisassembly of the parts, removal and reapplication of the wheel fromand to the spindle, or rearrangement of the various parts.

It is a further object of the invention to provide a truing device ofthis sort which utilizes plural interdependent adjusting means, all ofwhich become effectively locked in their respective adjusted positionswhen a final adjustment on the last adjusting means of the series hasbeen made.

The provision of a truing device for peripheral type diamond grindingwheels which is in the form of an adjustable mounting having a minimumnumber of relatively movable parts and which, therefore, is unlikely toget out of order; one which is rugged and durable and which, therefore,will withstand rough usage; one which is simple in its construction andwhich is thus easy to operate; and one which otherwise is'well adaptedto perform the services required of it, are further desirable featureswhich have been borne in mind in the production and development of thepresent invention.

Numerous other objects and advantages of the inven tion, not at thistime enumerated, will become more readily apparent as the followingdescription ensues.

In the accompanying single sheet of drawings forming a part of thisspecification, two illustrative embodiments of the invention have beenshown.

In these drawings:

Fig. 1 is a front elevational view partly in section of a peripheraltype grinding wheel showing the same operatively mounted on a centraladaptor by means of the present truing device;

Fig. 2 is a side elevational view, partly in section, of the structureshown in Fig. 1;

Fig. 3 is a quarter sectional view taken substantially along the line 33of Fig. 2; and

Fig. 4 is an enlarged fragmentary detail sectional view taken on aradial plane transversely through a modified form of the truing device.

Referring now to the drawings in detail and in particular to Figs. 1 and2, a conventional peripheral type diamond grinding wheel is designatedin its entirety at 10 and comprises the usual wheel body or annulus 12provided with a central circular mounting or arbor opening 14 thereinand the outer periphery of which has mounted thereon a matrix assembly16 consisting of crushed or fragmented diamonds. The grinding Wheel 10is shown as being mounted on a conventional adaptor 18 having arearwardly disposed radial clamping head 20 and a threaded shank portion22 by means of the truing or mounting device of the present inventionand which will shortly be described in detail. The adaptor 18 is carriedat the outer tapered end 24 of a drive shaft or spindle 26, associatedwith a conventional grinding machine (not shown) the end 24 fittingwithin a tapered bore 28 provided in the spindle. A clamping nut 30which is countersunk in the adaptor 18 and threaded as at 32 on thereduced end of the spindle 26 serves to secure the adaptor on thespindle for rotation in unison therewith.

In the form of the invention shown in Figs. 1 to 3, inclusive, themounting device per se is designed in its entirety at 34 and iscomprised of four annular parts including a rear clamping ring 36, afront clamping ring 38, an intermediate radially shiftable centeringring 40, and a pull-up or clamping nut 42. The device further includes aseries of adjusting or centering screws 44 of which there preferably arefour in number although a greater or lesser number of such screws may beemployed if desired.

The rear clamping ring 36 is in the form of a relatively thick circularplate having a central hub portion 46 of uniform thickness presenting afiat radial rear side 48 which fits against a forwardly facing annularshoulder 56 formed on the adaptor head 20, and having an outerfrusto-conical rear surface 52 of small slant height. The outer portion54 of the ring 36 is of less thickness than the thickness of the hubportion 46 and has formed thereon a forwardly facing circular ribpresenting a flat annular clamping surface 55 adapted to bear againstthe rear side of the wheel body 12. The front clamping ring 38 issi1nilar in its design to the ring 36 and includes a central hub portion56 presenting a flat radial front face 57 and having an outerfrusto-conical surface 58 of small slant height. The outer portion 66 ofthe ring 38 is of less thickness than the thickness of the hub portion54 and has formed thereon a rearwardly facing circular rib presenting afiat annular clamping surface 62 which opposes the surface 55 and isadapted to bear against the front side of the Wheel body 12 so that thelatter may be clamped between the two surfaces 55 and 62. The clampingnut 42 is adapted to be tightened on the threaded shank portion 22 ofthe adaptor 13 to draw the various parts together, thus clamping the tworings 36 and 33 between the nut 42 and shoulder t on the adaptor head 20and, in turn, clamping the inner peripheral regions of the wheel body 12between the surfaces 55 and 62 in selected positions of adjustment ofthe wheel under the control of the various adjusting screws 44 in amanner that will be made clear presently.

The ring 40 fits within the central opening 14 in the grinding wheel 12with a tight frictional fit, there being no lost motion between thesetwo parts. The ring 40 is of small radial width and the inner and outerperipheral edges 64 and 66 thereof respectively are truly cylindrical.The inner peripheral edge 64 is formed with a series of semi-circularrecesses 68, four such recesses being shown for illustrative purposes aswell as for most elficient operation of the device although a greater orlesser number of the recesses may be employed if desired. The fourrecesses 68 are circumferentially spaced with adjacent recesses being 90from each other so that each recess is diametrically opposed by one ofthe other recesses. The outer surface 70 afforded by the hub portion 46of the rear ring 36 is truly cylindrical and it is formed with a seriesof four similarly spaced semi-circular recesses 72 designed foropposition to and register with the four recesses 68 in the ring 40. Theexternal diameter of the hub portion 46 of the ring 36 is slightly lessthan the internal diameter of the ring 40 so that the hub and ring arenormally separated by a narrow circular space 74 (see particularly Fig.3) with the former being capable of limited radial adjustment in anydesired direction within the latter by means of the adjusting screws 44as will be described in detail.

The opposed pairs of semi-circular recesses 68 and 72 define, in effect,therebetween four holes or split openings which are spaced 90 apart andeach of which has its opposite walls threaded, thus providing a seriesof interrupted threads, each adapted to receive therein in threadedrelationship one of the adjusting screws 44. The

. adjusting screws are of conventional threaded tapered design, thescrews preferably being inserted into their respective split openingsfrom the front side thereof and being capable of adjustment from thefront of the machine, utilizing a suitable tool such as an Allen typewrench which may be passed through a series of openings 76 provided inthe ring 33 in alignment with the split openings and received inhexagonal sockets 78 (Fig. 3) which are characteristic of screws of thistype. Additional openings 80 are formed in the rear ring 36 in alignmentwith the openings 76 and afford the necessary clearance for the smallends of the tapered screws 44.

The clamping nut 42 may be of the circular type and is formed with apair of diametrically opposed spaced holes 75 therein designed forcooperation with a suitable tool such as a spanner wrench or the likeand by means of which the hub may be tightened on the threaded shankportion 22 of the adaptor 18.

In operation of the above described mounting device 34, the grindingwheel iii is first mounted on the adaptor 18 with the ring 46 fittedwithin the arbor openings and with the ring 44) disposed between theopposed inner faces of the 36 and 38 in floating relationship withrespect thereto and with the pull-up nut 42 drawn up loosely against thefront face 57 of the front clamping ring 38. It is then necessary onlyto insert a wrench into and through one or more of the openings 76 inthe ring 38 and into the hexagonal sockets 73 for proper cooperationwith one or more of the adjusting screws 44, turning the latter in onedirection or the other to advance or retract the same longitudinally inthe split openings afforded by the opposed semi-circular threadedportions 63 and 72 and thus bring the floating ring 46, andconsequently, the grinding wheel 16, to a precise adjustment wherein anindicating instrument or gauge will indicate that the diamond matrix ofthe wheel is true with respect to the axis of the spindle 26.Ordinarily, truing of the grinding wheel it) in this manner will, to alarge extent, compensate for any unbalanced forces which might otherwisearise in the rotating wheel and the latter will be in perfect balance,as well as being true on the driving spindle.

During the actual adjusting operation as described above, turning of anyone of the adjusting screws 44 in a direction to advance the sameaxially in the split opening provided for it will serve to spread theopposed semicircular walls of the recesses 68 and 72 apart by a combinedcarnming and wedging action, thus applying a direct radial thrust to thering 4%, or, depending upon the particular setting of the otheradjusting screws, applying a vectorial component of radial thrust to thering. Experience will dictate the particular order of adjustment of thevarious screws 44 as well as the extent to which each screw shall beturned to effect the desired adjustment. The adjusting of the last screw44 in the series will effect a four-way binding of the ring 46 andtightening of that particular screw against the recess wall 68 will drawthe ring firmly into locking engagement with all of the adjusting screwsso that the inwardly directed counter-thrust applied thereto will lockthe grinding wheel in its final adjusted position. After the necessaryadjustment of the screws 44 has been made, the clamping screw 36 may betightened against the adapter 26 and the machine set into 7 operation.

In the form of the invention shown in Fig. 4, the front and rearclamping rings remain substantially the same as in the previouslydescribed form shown in Figs. 1 to 3, inclusive. In this instancehowever, the intermediate ring 4-0 has been omitted. To avoid needlessrepetition of description, similar reference numerals of a higher orderhave been applied to the corresponding parts in Fig. 4. With theintermediate ring 40 omitted, the inner periphery 114 of the grindingwheel body 112 is provided with semicircular threaded recesses 168 whichcooperate with the opposed threaded recesses 172 formed in the hubportion 146 of the rear clamping ring 136 and with the adjusting screws144 in the manner previously described in connection with the recesswalls 68 and 72 and adjusting screws 44. In this instance, the radialthrust or the vectorial thrust occasioned by the spreading action of theadjusting screws 144 will be applied directly to the grinding wheel body112 instead of through the intermediate ring 40 as in the other form ofthe invention.

The purpose of the ring 40 in the previously described form of theinvention is threefold. Firstly, since it is of greater thickness thanthe body of the grinding wheel body 12, it affords greater thread areaand consequently a more positive spreading action, as well as betterfriconeness tional binding characteristics; secondly, it extends theradial reach of the clamping surfaces 55 and 62 to secure a betterclamping action there between on the wheel body; and thirdly, iteliminates special machining of the grinding Wheel body which, ofcourse, is unnecessary where the latter is to be installed on an adaptordirectly and without benefit of the advantages of the present invention.

in compliance with title 35' U. S. Code, section 22, a preferred form ofthe invention and one modification thereof have been shown in thedrawings and described herein, but it should be understood that theinvention is not to be limited to the specific disclosure made inasmuchas various changes in the details of construction may be resorted towithout departing from the spirit of the invention. The ensuing claimstherefore should be construed as broadly as the prior art will permit.

Having thus described the invention what l claim as new and desire tosecure by Letters Patent is:

i. In a device for operatively mounting a peripheral type grinding wheelor the like having a mounting opening therein on a machine spindlebetween a shoulder normal to and rotating with the spindle and a pull-upnut on the forward end of the spindle, in combination, front and rearclamping rings surrounding the spindle between said shoulder and nut inconcentric relation with respect to the spindle and in engagement withthe opposite faces respectively or" the wheel in clamping relationthereto under the influence of said pull-up nut, a hub portion formed onsaid rear clamping ring presenting an outer cylindrical surface, anintermediate mounting ring fitting within said mounting opening of thewheel and surrounding said cylindrical surface on the hub and spacedfrom the latter, said intermediate ring being loosely disposed betweensaid front and rear clamping rings and capable of radial adjustmentrelative to the hub in any angular direction, and an adjustable wedgemember interposed between said hub and intermediate ring at at leastthree widely and circumferentially spaced regions therearound, saidwedge members each being operable upon progressive adjustment thereof inone direction to exert increasing increments of outward radial thrust onthe intermediate ring member.

2. In a device for operatively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim 1wherein said wedge members are each shiftable in opposite directionslongitudinally of the spindle and grinding wheel.

3. In a device for operatively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim lwherein each of said wedge members is in the form of a tapered bodyhaving opposite side surfaces in sliding contact with the outercylindrical surface of the hub and the inner peripheral surface of saidintermediate ring respectively.

4. in a device for operatively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim 1wherein each of said wedge members is in the form of a longitudinallyextending tapered adjusting screw having a frusto-conical threadedsurface in threaded engagement with the outer cylindrical surface of thehub and the inner peripheral surface of said intermediate ringrespectively.

5. In a device for operatively mounting a peripheral type grinding wheelor the like having an arbor open ing therein on a machine spindlebetween a shoulder normal to and rotating with the spindle and a pull-upnut on the forward end of the spindle, in combination, front and rearclamping rings surrounding the spindle between said shoulder and nut inconcentric relation with respect to the spindle and in engagement withthe opposite faces of the wheel respectively in clamping relationthereto under the influence of said pull-up nut, a hub portion formed onone of said clamping rings presenting an outer cylindrical surface, anintermediate mounting ring fitting within said mounting opening of thewheel and surrounding said cylindrical surface on the hub and spacedfrom the latter, said intermediate ring being loosely disposed betweensaid front and rear clamping rings and capable of radial adjustmentrelative to the hub in any angular direction, and an adjustable wedgemember interposed between said hub and intermediate ring at at leastthree circumferentially spaced regions therearound, said wedge memberseach being operable upon progressive adjustment thereof in one directionto exert increasing increments of outward radial thrust on theintermediate ring member.

s. in a device for operaively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim 5wherein each of said wedge members is in the form of a longitudinallyextending tapered adjusting screw having a frusto-conical threadedsurface in threaded engagement with the outer cylindrical surface of thehub and the inner peripheral surface of said intermediate ringrespectively.

7. In a device for operatively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim 5wherein each of said wedge members is in the form of a longitudinallyextending tapered adjusting screw having a frusto-conical thread-- edsurface, and in which the outer cylindrical surface of the hub and innerspaced surface of the intermediate ring are formed with opposedsemi-circular recesses at said clrcumferentially spaced regionsrespectively, each of which partially embraces and threadedly engagesone of said adjusting screws.

8. in a device for operatively mounting a peripheral type grinding wheelor the like on a machine spindle, the combination set forth in claim 5wherein said wedge members are four in number and are circiunferentiallyspaced apart.

9. in a device for operatively mounting a peripheral type grinding wheelor the like having an arbor opening therein on a machine spindle betweena shoulder normal to and rotating with the spindle and a pull-up nut onthe forward end of the spindle, in combination, front and rear clampingrings surrounding the spindle between said shoulder and nut inconcentric relation with respect to the spindle and in engagement withthe opposite faces of the wheel espectively in clamping relation theretounder the influence of said pull-up nut, a hub portion formed on one ofsaid clamping rings and extending axially into the grinding wheel arboropening, said hub portion presenting an outer cylindrical surface inradial opposition to and spaced from the inner peripheral edge of saidgrinding wheel, and an adjustable wedge member interposed between saidsurface and the inner peripheral edge of said grinding wheel at at leastthree circumferentially spaced regions therearound, said wedge memberseach being operable upon progressive adjustment thereof in one axialdirection to effectively exert increasing increments of outward radialthrust on the grinding wheel.

10. In a device for operatively mounting a peripheral type grindingwheel or the like on a machine spindle, the combination set forth inclaim 9 wherein said hub portion is formed on the rear clamping ring.

References Cited in the file of this patent UNITED STATES PATENTS2,675,653 Bryant Apr.20, 1954

